against convention

In Rails we have these nice things we can use in our controllers called filters. A filter is simply a method that will get executed before, after or around the execution of a specific action in a controller. After looking at a bunch of different Rails apps, I never liked any of the names given to these filter methods.

For example:

class UsersController < ApplicationController

  before_filter :ensure_logged_in

  def show
    @user = User.find params[:id]
  end

 private

  def ensure_logged_in
    unless session[:user_id]
      flash[:notice] = 'You must log in'
      redirect_to new_session_path
    end
  end

end

I’ve seen this technique of prefixing the word ‘ensure’ to filter names. I think this sucks and results in long ugly method names.

I’ve also seen this:

class UsersController < ApplicationController

  before_filter :require_logged_in

  def show
    @user = User.find params[:id]
  end

 private

  def require_logged_in
    unless session[:user_id]
      flash[:notice] = 'You must log in'
      redirect_to new_session_path
    end
  end

end

Prefixing all filter names with 'require’. Same thing as 'ensure’; long ugly method names.

I’ve adopted the following convention:

class UsersController < ApplicationController

  before_filter :logged_in?

  def show
    @user = User.find params[:id]
  end

 private

  def logged_in?
    unless session[:user_id]
      flash[:notice] = 'You must log in'
      redirect_to new_session_path
    end
  end

end

Now this flies in the face of normal Ruby use of the ’?’ operator, i.e. it should only be used for query methods (methods that return a boolean). But it reads so much better and the method name is nice and short.

Jared Carroll
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